Study of Thermal Insulation Properties of Nonwoven Fabrics from Recycled Textile Fibres for Building Applications

Building thermal insulation materials represent a growing market in Nigeria, driven by energy efficiency requirements and the increasing cost of air conditioning in tropical climatic zones. This study evaluates the thermal insulation properties of nonwoven fabrics produced from recycled textile fibres collected from garment cutting waste in Port Harcourt, Rivers State, South South Nigeria. Nonwoven panels were produced by needle-punching of blended polyester and cotton cutting waste at areal densities of 200, 400, and 600 gsm. Thermal conductivity was measured using a heat flow meter apparatus at mean temperatures of 23 and 40 degrees Celsius. Bulk density, thickness under standard pressure, compressive resilience, and sound absorption coefficient at 500 and 1000 Hz were characterised as supplementary performance metrics. Fire reaction was assessed using a cone calorimeter. Results show that 400 gsm panels achieved thermal conductivity of 0.041 W/m.K at 23 degrees Celsius, comparable to commercial glass wool insulation boards. Sound absorption coefficient at 1000 Hz reached 0.72 for 600 gsm panels, indicating effective acoustic insulation properties as a secondary benefit. Compressive resilience exceeded 85 percent after repeated loading cycles. Cone calorimeter results confirmed combustibility of untreated panels, with peak heat release rates of 120 kW/m2, indicating the need for flame retardant treatment for building application compliance. The study recommends recycled textile nonwoven panels as cost-effective thermal and acoustic insulation materials for residential buildings in South South Nigeria, pending integration of appropriate flame retardant finishing. Keywords: nonwoven fabric, recycled textile, thermal insulation, building applications, Port Harcourt